How to continue a dialog (GUI.Label) with answering Buttons?

Hi Guys,

I need help again, but this time, it is about scripting a dialog between my Player and a Cube (very cool, isn't it?)

Here is the Behaviour I would like to see:

• The Player approaches to the Cube and gets in its Trigger.

• The Player then presses "E" to start a conversation with that Cube.

• The GUI.Area with the conversation text appears like this:

• Now I would like to press the Button to continue the dialog, you know? It would just be like in The Elder Scrolls - Morrowind.

• The Cube would tell me something like: "The Quest-NPC is behind that house" and I would Click on the appearing OK-Button to Close the whole Dialog.

Basically I would like to see the second Part of the text only if I clicked on the button in the dialog.

But if I click this Button, nothing happens.

Here is my Script:

     if (other.gameObject.tag == "NPC"){
         
         NPCtalk = true;
         if(Input.GetKeyUp(KeyCode.E)){
             
             startdialog = true;
             item_name = other.gameObject.name;
             playername = "Ark";
             
             }
             }    
             }
     
     
     void OnTriggerExit(Collider other){
         NPCtalk = false;
         WeaponPickup = false;
     }
     
         void OnGUI(){
             if (WeaponPickup){
                 GUI.Label (new Rect (500,500,1000,1000), "[E] Waffe aufnehmen"); 
             }
             
             if (NPCtalk){
                 GUI.Label (new Rect (500,500,1000,1000), "[E] Reden"); 
             }
             if (startdialog){
                 NPCtalk = false;
                 if (item_name == "Cube"){
                 
                 GUILayout.BeginArea(new Rect(100,100,200,200));
                 GUILayout.Label(item_name + ": Alter...du redest mit einem Wuerfel...");
                 if (GUILayout.Button(playername + ": Ich geh dann mal weiter")){
                     GUILayout.Label(item_name + ":...den Questgeber findest du hinter dem Haus.");
                             if (GUILayout.Button("OK")){
                             
                                 
                 }
                 }
             }
                 
                 GUILayout.EndArea();
                 
                 
             
             }
            
           }
             }